JPH0735250A - Valve device - Google Patents

Abstract

PURPOSE:To improve reliability in preventing backflow of water at the time of water failure or the like by forming a part between a check valve mechanism in the secondary side chamber and a valve port as a negative pressure isolating chamber, and providing a negative pressure isolating valve mechanism in a valve device in which a valve body is actuated by balance of pressure applied on the valve body and a pressure receiving body. CONSTITUTION:In a normal actuation condition, a check valve mechanism 25 is in a valve open condition to actuate as a normal pressure reducing valve. In the meanwhile, when siphone phenomenon occurs by water failure or the like, forming a negative pressure on the primary side, the check valve mechanism 25 closes a valve, and the negative pressure acts on a lower surface of a valve body 6 to close the valve body 6. At the timing when this primary side pressure is reduced almost to an atmospheric pressure, a slide valve 33 at a negative pressure isolating valve mechanism 30 moves down by its own 'weight in a communication passage 31 inside a valve shaft 8 to communicate a negative pressure isolating chamber 4 with an atmospheric pressure communication chamber 13 through a communication hole 32. In this condition, if leak occurs at a packing 7 or the like in the valve body 6, a negative pressure is not generated because the inside of the negative pressure isolating chamber 4 is communicated with open air, thereby danger of undesired opening of the valve body 6 can be eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve device for water supply equipment having a structure in which the valve body is actuated by the balance of the pressure acting on the valve body and the pressure receiving body. The present invention relates to a valve device that can reliably prevent the occurrence of More specifically, the present invention is a valve device such as a pressure reducing valve device, a constant flow valve device, a constant pressure valve device, a water shutoff valve device, etc., which is arranged near a water meter of a water main of a water supply facility. The present invention relates to a valve device capable of reliably preventing reverse flow of tap water when the primary side has a negative pressure due to the San Hong phenomenon.

[0002]

2. Description of the Related Art Conventionally, as a pressure regulating valve device used in water supply facilities, for example, as a pressure reducing valve, a water pressure at a predetermined pressure reducing ratio is obtained by a balance between water pressure acting on a valve body and water pressure acting on a pressure receiving body. There is a type to reduce the pressure. Such a pressure reducing valve device includes a valve body that opens and closes a valve opening, and a pressure receiving body connected to the valve body. Then, for example, the pressure on the primary side acts on the lower surface of the valve body and the pressure on the secondary side acts on the pressure receiving body, and the pressure receiving area of this valve body and the pressure receiving area of the pressure receiving body are the decompression ratio. Etc. are set to a predetermined ratio.

Therefore, in such a pressure reducing valve device, when the pressure on the primary side and the pressure on the secondary side have a predetermined pressure reducing ratio, this valve body and the pressure on the secondary side acting on the pressure receiving body are balanced. The opening degree of the valve body is kept constant, and the pressure is reduced at a predetermined pressure reduction ratio. Further, when the pressure on the primary side or the secondary side fluctuates, the balance is disturbed, and the opening degree of this valve element changes until the pressure on the primary side and the pressure on the secondary side reach a predetermined pressure reduction ratio, The predetermined pressure reduction ratio is maintained again.

The valve device of this type is also used as a constant flow valve device and a constant pressure valve device, and is arranged, for example, in the vicinity of a water meter of a water main to adjust the supplied pressure, and It is used as a valve device that also functions as a water shutoff valve.

By the way, in water supply facilities, when water is cut off, a siphon phenomenon may occur due to a difference in height of the pipes, which may cause negative pressure inside the pipes and valves. In such a case, a back flow of tap water occurs, which is not preferable in terms of hygiene. Conventionally, a building or a high-rise condominium is provided with a water receiving tank, and water supplied from a water supply facility is once stored in the water receiving tank and then supplied to a faucet or the like at each end. However, recently, a so-called direct water supply system in which such a water receiving tank is omitted and a main pipe of a water supply is directly connected to a faucet or the like at an end is being adopted.

[0006] Such a direct water supply system is excellent in hygiene since tap water is not stored in the water receiving tank, but on the other hand, when the siphon phenomenon occurs as described above, the sewage flows backward from the faucet at the end, There is also a drawback that the inside of the pipe is contaminated. In order to overcome such drawbacks, it is important to provide a vacuum breaker in the middle of the water pipe, provide check valves at various places in this water pipe, and give backflow prevention functions to the opening / closing valves of water facilities. Is.

However, even in such a check valve or a valve device having a check flow prevention function, in order to surely prevent the check flow even if internal leakage occurs, a double check valve mechanism is provided in series. It is necessary to use the so-called double-jack type provided in the. Therefore, the valve device used for such a direct water supply type water supply facility has a complicated structure and is costly.

By the way, in the valve device as described above, if the valve body is configured to be seated on the valve opening from the secondary side, when the siphon phenomenon occurs and the primary side becomes negative pressure, The negative pressure causes the valve element to sit on the valve opening and act as a check valve mechanism, so if one check valve mechanism is added to such a pressure reducing valve, the structure of the double-jack type is substantially achieved. The structure is simple and the cost can be kept low.

However, in such a check valve device, if leakage occurs in the packing of the valve body or the like, if the primary side becomes negative pressure, the upstream side of the check valve mechanism on the secondary side. There is a possibility that the portion of will also become negative pressure and negative pressure will also act on the pressure receiving body. In such a case, the valve body may be fully opened by the negative pressure acting on the pressure receiving body, and in such a case, the reliability of the double-jack type backflow prevention cannot be obtained.

[0010]

The present invention has been made based on the above circumstances, and in the valve device such as the pressure reducing valve as described above, one check valve mechanism is added and the valve body should be provided. Even if a leak occurs in the valve, the valve does not open, and the reliability of the backflow prevention function that is substantially equivalent to that of the double-jack type can be obtained, and the structure is simple and the cost can be kept low. Form valve device.

[0011]

SUMMARY OF THE INVENTION The present invention is directed to a valve body which is seated on the valve opening from the secondary side to open and close the valve opening, and a pressure receiving body which is connected to the valve opening and receives the pressure on the secondary side. In the valve device for operating the valve body by the balance between the pressure on the primary side acting on the valve body and the pressure on the secondary side acting on the pressure receiving body, in the secondary side chamber, Side check valve mechanism that allows only the flow in the direction from the secondary side to the secondary side, the part between the check valve mechanism and the valve port of the secondary side chamber is formed in the negative pressure cutoff chamber, and A negative pressure cutoff valve mechanism is provided which connects the negative pressure cutoff chamber and the atmosphere and allows a flow in the direction from the atmosphere side to the negative pressure cutoff chamber.

[0012]

[Operation] When the Sanhong phenomenon occurs due to water cutoff and the primary side becomes negative pressure, this negative pressure acts on the valve body, and this negative pressure causes the valve body to sit on the valve opening and close the valve opening. It Therefore, this valve body functions as a check valve, and functions as a double check type check valve device in cooperation with the above-mentioned added check valve mechanism.

If a leak occurs in the packing of the valve body, the negative pressure on the primary side also acts in the negative pressure cutoff chamber. However, the negative pressure cutoff valve mechanism described above is used. Is opened and the inside of this negative pressure cutoff chamber becomes atmospheric pressure. Therefore, even in such a case, the negative pressure does not act on the pressure receiving body, and the valve body does not open.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. This example is a pressure reducing valve device for a water supply facility. Reference numeral 1 in the figure is a valve box, and in the valve box 1, a primary side chamber 2 on the primary side and a secondary side chamber 3 on the secondary side are formed, and the primary side chamber 2 and the secondary side chamber 3 are valves. It is communicated through the mouth 5. A strainer 9 is provided in the primary chamber 2 so as to surround the valve opening 5 and is configured to remove foreign matters and the like.

A valve element 6 is seated on the valve opening 5 from the secondary chamber 3 side, and the valve opening 5 is opened and closed. A packing 7 is provided on the valve body 6 to maintain liquid tightness when seated on the valve opening 5. Further, a valve shaft 8 is provided on the valve body 6 so as to project upward, and a pressure receiving body 10 is attached to an upper end portion of the valve shaft 8. The area of the pressure receiving body 10 is larger than the area of the valve body 6 and is set to a predetermined area ratio corresponding to a predetermined pressure reduction ratio.

Further, a pressure receiving body accommodating chamber 11 is formed in the upper part of the valve box 1, and the pressure receiving body 10 is slidably accommodated in the pressure receiving body accommodating chamber 11 in a liquid-tight manner. . The pressure receiving body 10 allows the pressure receiving body accommodation chamber 11
The interior is divided into two compartments, one compartment being formed in the pressure chamber 12 and the other compartment being formed in the atmosphere communication chamber 13. The pressure chamber 12 communicates with the secondary side by a pressure guiding passage 15. Further, the atmosphere communication chamber 13 is communicated with the atmosphere through the small holes 14.

A stopper mechanism 20 is provided at the upper end of the pressure receiving body accommodating chamber 11. The stopper mechanism 20 includes a stopper rod 21 provided so as to be vertically screwed.
Is equipped with. The stopper rod 21 faces the upper end portion of the valve shaft 8 and contacts the upper end portion of the valve shaft 8 when the valve body 6 opens to raise the valve body 6. It is configured to regulate the amount, that is, the opening degree.
In addition, the stopper rod 21 is screwed to adjust its position so that the maximum opening degree of the valve body 6 is arbitrarily set.

In the pressure reducing valve device configured as described above, the high-pressure water pressure on the primary side acts on the lower surface of the valve body 6 and pushes up the valve body 6 to urge it in the valve opening direction. On the other hand, the water pressure on the secondary side is transmitted through the pressure guiding passage 15 to the pressure chamber 12
It is introduced inside and acts on the upper surface of the pressure receiving body 10. Therefore, the pressure receiving body 10 is pushed down by the pressure on the secondary side, and urges the valve body 6 in the direction to close it.

Since the pressure receiving area between the valve body 6 and the pressure receiving body 10 is set to a predetermined area ratio, a force for urging the valve body 6 in the direction of opening the valve body 6 by the above primary side pressure,
In a state where the pressure on the secondary side balances the force for urging the valve body 6 in the closing direction, the valve body 6 is maintained at the opening degree at that time. Therefore, in this case, the pressure on the primary side and the pressure on the secondary side have a predetermined decompression ratio, and a predetermined decompression is performed by this decompression valve device. When a change in the flow rate, a change in the pressure on the primary side or the secondary side, or the like occurs, the balance between the urging force acting on the valve body 6 and the force acting on the pressure receiving body 10 is lost, and the valve body When the opening degree of 6 changes and the pressure on the primary side and the pressure on the secondary side reach a predetermined pressure reduction ratio, the balance is brought into a balanced state again. Therefore, this pressure reducing valve device always reduces the pressure on the primary side at a predetermined pressure reducing ratio.

Further, in the pressure reducing valve device of the present invention, a backflow preventing function is added to prevent backflow when the siphon phenomenon occurs due to water cutoff or the like and the primary side becomes negative pressure. explain.

That is, a check valve mechanism 25 is provided in the secondary side chamber 3 described above. This check valve mechanism 25
It has a normal configuration and allows only the flow in the direction from the valve body 6 side. Further, the valve body 26 of the check valve mechanism is obliquely arranged so as to reduce the flow resistance when water flows. In addition, this valve body 26
Is biased in the valve closing direction by a spring 27.

Further, the valve body 6 has the valve opening 5 from the secondary side.
When the primary side becomes negative pressure, the negative pressure urges the valve body 6 in the valve closing direction, so that the valve body 6 functions as a check valve mechanism. Have Therefore, the check valve mechanism 25 and the valve body 6 form a double-jack structure, and a part of the secondary side chamber between the check valve mechanism 25 and the valve body 6 is It is formed as a negative pressure cutoff chamber 4.

However, as described above, in the unlikely event that leakage occurs in the packing 7 of the valve body 6 or the like and the inside of the negative pressure cutoff chamber 4 becomes negative pressure, the negative pressure acts on the pressure receiving body 10. As a result, the valve body 6 is opened, and the reliability of backflow prevention as a double check cannot be obtained. The pressure reducing valve device employs the following configuration that prevents the above-mentioned problems.

That is, a vacuum breaker 28, which is a first negative pressure cutoff valve mechanism, is attached to the bottom wall of the pressure receiving body accommodating chamber 11. The vacuum breaker 28 has a normal structure as shown in FIG. 3, and includes a main body 41 formed of a synthetic resin material or the like and a valve body 42. The valve body 42 is biased in the valve closing direction by a spring 43. Reference numeral 44 is a guide member for the valve body 42. Such a vacuum breaker 28
Is opened when the inside of the negative pressure cutoff chamber 4 becomes a negative pressure, and the atmosphere in the atmosphere communication chamber 13 is introduced into the negative pressure cutoff chamber 4, and the inside of the negative pressure cutoff chamber 4 becomes negative. It prevents pressure.

In addition to the vacuum breaker 28 described above, a second negative pressure cutoff valve mechanism 30 is provided. The negative pressure cutoff valve mechanism 30 includes a communication passage 31 formed in the valve shaft 8 described above. The upper end of the communication passage 31 is opened to the upper end of the valve shaft 8 and communicates with the atmosphere communication chamber 13, and the lower end is opened to the lower end surface of the valve shaft 8 and the primary chamber 2 It communicates with the inside. In addition, this communication passage 3
The middle of 1 communicates with the inside of the negative pressure cutoff chamber 4 through the communication hole 32. Further, a sliding valve body 33 is slidably provided in the communication passage 31. This sliding valve body 33
Is configured to slide up and down to close the upper end or the lower end of the communication passage 31.

The sliding valve element 33 is normally pushed up by the pressure on the primary side and closes the upper end of the communication passage 31. Then, when the primary side has a negative pressure, as shown in FIG. 1, the negative pressure pulls the sliding valve element 33 downward to close the lower end of the communication passage 31. Therefore, in this state, the inside of the negative pressure cutoff chamber 4 communicates with the atmosphere communication chamber 13 via the communication passage 31 and the communication hole 32. The second negative pressure cutoff valve mechanism 30 has a better operational response than the vacuum breaker 28 described above, and cooperates with the vacuum breaker 28 to reliably prevent the negative pressure cutoff chamber 4 from becoming negative pressure. .

That is, the above vacuum breaker 28
Since the valve element 42 is biased by the spring 43,
Even if the negative pressure cut-off chamber 4 becomes slightly negative, the valve does not open. However, the sliding valve body 33 of the second negative pressure cutoff valve mechanism described above is
When the pressure on the primary side is reduced to almost equal to the atmospheric pressure, it is lowered by its own weight, and the inside of the negative pressure cutoff chamber 4 is opened to the atmosphere communication chamber
Communicate with.

A discharge valve mechanism 29 is provided at the bottom of the negative pressure cutoff chamber 4. This discharge valve mechanism 29
Are configured as shown in FIG. That is, reference numeral 50 in the drawing is a main body, and the check valve body 5 is provided in the main body 50.
1 is provided. A valve port 53 is provided below the check valve body 51, and the check valve body 51 has the valve port 5
3 is seated on the upper side, that is, from the negative pressure cutoff chamber 4 side, and the valve opening 53 is closed. The check valve body 51 is biased upward by the spring 52, that is, in the valve opening direction. Further, a plurality of cutouts 54 are formed in the peripheral portion of the check valve body 51, and when the check valve body 51 is biased upward by the biasing force of the spring 52 and is separated, Water is circulated through the notch 54. Further, an opening / closing valve such as a cock 55 is attached to the lower portion of the main body 50, and the cock 55 is normally left open.

Next, the operation of such a backflow prevention type pressure reducing valve device will be described. In a normal operation state, the check valve mechanism 25 is in a valve open state and operates as a normal pressure reducing valve. In this case, the discharge valve mechanism 29 is used in the negative pressure cutoff chamber 4
The check valve body 51 is pushed down by the internal pressure to close the valve port 53, and the discharge valve mechanism 29 is in the valve closed state.

When the siphon phenomenon occurs due to water interruption or the like and the primary side becomes negative pressure, the check valve mechanism 25 is closed and negative pressure acts on the lower surface of the valve body 6, This valve body 6 closes. Therefore, this valve device has the same reliability of the backflow preventing function as the double check valve having the double check valve mechanism.

In the actual operation, when the pressure on the primary side decreases due to the siphon phenomenon or the like, the sliding valve body 33 is reduced when the pressure on the primary side decreases to almost atmospheric pressure.
Is lowered by its own weight and the negative pressure cutoff chamber 4 is communicated with the atmosphere communication chamber 13 through the communication passage 31 and the communication hole 32. Therefore,
Should a leak occur in the packing 7 etc. of the valve body 6,
The water in the negative pressure cut-off chamber 4 is drawn into the primary side through the leak point of the valve body 6, but since the inside of the negative pressure cut-off chamber 4 is communicated with the atmosphere as described above, this negative pressure Shut-off chamber 4
The inside is maintained at atmospheric pressure and never becomes negative pressure. Therefore, negative pressure does not act on the pressure receiving body 10,
The valve body 6 does not open undesirably.

When the pressure inside the negative pressure cutoff chamber 4 becomes atmospheric pressure, the check valve body 51 of the discharge valve mechanism 29 is opened by the urging force of the spring 52, and the inside of the negative pressure cutoff chamber 4 is opened. Water is discharged to the outside through the discharge valve mechanism 29. Therefore, in the unlikely event that the check valve mechanism 25 leaks,
Even if a backflow occurs in the negative pressure cutoff chamber 4, the backflowed water is discharged to the outside from the discharge valve mechanism 29, so that the water is reliably prevented from flowing back to the primary side. When the leaked water is large, the vacuum breaker 28 is opened and a large amount of air is introduced into the negative pressure cutoff chamber 4, so that a backflow may occur in such a case. There is no.

The present invention is not limited to the above embodiment. For example, in the above-described embodiment, the first and second negative pressure cutoff valve mechanisms are provided as the negative pressure cutoff valve mechanism, but the present invention is not limited to this and one negative pressure cutoff valve mechanism is provided. It may be a valve mechanism. The discharge valve mechanism does not always have to be provided.

Furthermore, the present invention is not limited to the pressure reducing valve device as described above. As described above, the valve device of the type that adjusts the opening degree of the valve body by the balance of the pressure acting on the valve body and the pressure receiving body is not limited to the pressure reducing valve as described above, but may also be a constant flow valve, a constant pressure valve or the like. Also applies. Also, a small on-off valve is connected to the pressure chamber via piping etc., and the pressure in this pressure chamber is controlled by opening and closing this small on-off valve, which is also applied as an on-off valve for opening and closing the valve element. it can.
Therefore, the present invention is not limited to the pressure reducing valve device as described above, and it is needless to say that the present invention can be applied to a general valve device of a type that is operated by the balance of the pressures acting on the valve body and the pressure receiving body.

[0035]

As described above, according to the present invention, it is possible to obtain the reliability of the backflow prevention function which is substantially equal to that of the double check valve having the double check valve mechanism by only adding one check valve mechanism. Moreover, the structure is simple and the manufacturing cost can be reduced. In addition, a negative pressure cutoff valve mechanism was provided to prevent negative pressure from acting on the negative pressure cutoff chamber to open the valve disc in the event of a leak, so the reliability of backflow prevention is extremely high. And so on.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an embodiment of a check valve device of a backflow prevention type.

FIG. 2 is a vertical sectional view of a discharge valve mechanism.

FIG. 3 is a vertical cross-sectional view of a vacuum breaker.

[Explanation of symbols]

 1 ... Valve box 2 ... Primary side chamber 3 ... Secondary side chamber 4 ... Negative pressure shutoff chamber 5 ... Valve 6 ... Valve element 10 ... Pressure receiving body 25 ... Check valve mechanism 28 ... Vacuum breaker 29 ... Discharge valve mechanism 30 ... Negative pressure Shut-off valve mechanism

Claims (2)

[Claims] 1. A valve box, a primary side chamber and a secondary side chamber formed in the valve box, a valve port communicating the primary side chamber and the secondary side chamber, and a secondary side seated on the valve port. A valve body that opens and closes the lever valve opening and a pressure receiving body that is connected to the valve opening and receives the pressure on the secondary side, and the primary pressure acting on the valve body and the pressure receiving body on the pressure receiving body. In the valve device that operates this valve body by the balance with the acting secondary side pressure, a check valve mechanism that allows only the flow in the direction from the primary side to the secondary side is provided in the secondary side chamber, The part between the check valve mechanism and the valve port of the secondary side chamber is formed in the negative pressure cutoff chamber, communicates the negative pressure cutoff chamber with the atmosphere, and from the atmospheric side to the negative pressure cutoff chamber. A pressure regulating valve device comprising a negative pressure shut-off valve mechanism which allows only a flow in a forward direction. 2. The bottom of the negative pressure cutoff chamber communicates with the outside, and when the pressure in the negative pressure cutoff chamber becomes equal to the atmospheric pressure, the valve is opened, and the liquid in the negative pressure cutoff chamber is discharged to the outside. The valve device according to claim 1, further comprising a discharge valve mechanism for discharging.